23 July 2024

About NN-OnLine

Last updated 26 August 2005

  1. Who, what, where
  2. Some technical details
  3. Conditions of use
  4. How you can contribute to NN-OnLine
  5. Contact: questions, comments, ....
  6. Disclaimer
  7. Acknowledgements

1. Who, what, where

NN-OnLine was initiated by the Nijmegen group in 1994. Via this website we want to make some of the work of current and former members of the Theoretical High Energy Physics Group of the Radboud University Nijmegen, the Netherlands, more accessible for the physics community. It especially concerns the work on the baryon-baryon interaction: the nucleon-nucleon (NN) interaction, hyperon-nucleon (YN) interaction, antinucleon-nucleon (NN) interaction, and pion-nucleon (πN) interaction.

The interactive part of NN-OnLine allows you to instantaneously calculate and plot phaseshifts, scattering amplitudes and observables for several models of the NN interaction. Moreover you can browse the complete world database of low and intermediate energy nucleon-nucleon scattering data and compare the data with model predictions.

The NN-OnLine server is physically located somewhere in the aforementioned department.

2. Some technical details

Valid XHTML 1.1! Valid CSS!

The NN-OnLine server is a Hewlett Packard 9000 C360 computer. It has 1 GB memory and is running on HP-UX 11.11. It was cheaply bought in 2003 (and upgraded in 2005) to replace a then 12 year old machine.

We use the apache httpd daemon as server software.

Webpages are dynamically generated with PHP. The resulting HTML adheres to the XHTML standard of the World Wide Web Consortium (W3C). The pages allow you to check this for yourself by following the link offered by the W3C XHTML check logo. Stylesheets are used to provide the browser instructions on the preferred presentation of the pages. The stylesheets adhere to the W3C standards and again you can check that by following the link offered by the logo. Bitmap graphics, like logos and photographs, are all in either PNG or JPEG format. This is a GIF free site.

In the real spirit of the World Wide Web no evil proprietary vendor-extensions are used. Any browser (graphical and non-graphical) should therefore be able to be used to get information from NN-OnLine. Browser support for Java or ECMAscript (a.k.a. JavaScript) is not needed.

As our pages are authored to adhere to W3C standards, any browser that accepts these standards (and that should be any browser!) should be able to properly display our pages. Most modern browsers have no problems with that. Microsofts Internet Explorer, however, is not among those. Although it is the most used browser, it is quite outdated and crippled when it comes to properly implementing the W3C standards. Superior (and free!) alternatives are the excellent Mozilla/Firefox and Opera browsers. Even text-only browsers can be used. Some people still use a variety of the old Netscape 4 browser. Often that is by necessity rather than by choice. Although the pages don't look pretty, everything (still) works fine with Netscape 4.

Eprints can be obtained in their original REVTeX format, PostScript, or PDF, and where available, links to the electronic version of the 'official' publication are given.

Dynamically generated figures can be made in PostScript, PDF, PNG, SVG, or VRML format. You may need an (appropriately configured) viewer or plugin on your system to display them. The 2d plots are made with the locally developed Plot03, a descendant of the PlotPS package by Caspar Terheggen while the 3D surface plots are made using the DISLIN-library.

All programs that are used in the interactive part of NN-OnLine are written in fortran (currently a mixture of fortran 77 and fortran 95, using some non-standard extensions) with a little bit of c to interface with system libraries or external libraries. The programs (still) communicate with the server using the (browser independent) CGI protocol. Information and code On how to use CGI in fortran is available upon request.

The time needed for actual computations should be limited, there are a few exceptions though. Remember that the more you ask for - the more time it will take. In general the time needed for these computations should be at most about 10 seconds. Response times that are much longer either indicate a bug in the programs or congestion of the net.

3. Conditions of use

NN-OnLine is the product of scientific activity, please treat it as such. If you use information from NN-OnLine, please bear this in mind:
1) Always use the proper reference to the publication of the used potential, PWA, or experimental data.
2) A reference to NN-OnLine by at least mentioning the URL would be greatly appreciated.

4. You can contribute to NN-OnLine

First by letting us know if NN-OnLine was useful for you; if you have complaints, or suggestions to improve NN-OnLine. If you find any errors, or have additional or new information that would make NN-OnLine more useful, please let us know.

Second by helping us to complete, extend and document the database. NN-OnLine has the facility to link to preprints/papers and pages with other information about the data and experiments already built in. Any help and information from you that may help us and others to treat the data in a more useful way to gain knowledge about the baryon-baryon interaction is appreciated. Especially when in (new) experiments the statistics are so good that it becomes important to have a detailed knowledge about the origins and treatment of systematical uncertainties!

5. Contact: Questions, comments, .....

Your feedback is greatly appreciated. Also if you have any questions on using NN-OnLine, feel free to ask. There is a special email address to contact us: which is displayed on every page. This is the easiest way to contact us. If you need or wish to send us hardcopy mail, or something by fax, please ask for current details.

6. Disclaimer

Although we do our best to make the programs and all other information free of errors and bugs we cannot guarantee that all information is correct.
If you obtain erroneous or questionable results from NN-OnLine please contact us and we will have a look at it.

7. Acknowledgements

The contributions of the following former and current members of the Theoretical High Energy Physics group of the Radboud University Nijmegen is acknowledged: René Klomp, J.J. de Swart, Th.A. Rijken, Caspar Terheggen, Rob Timmermans, Vincent Stoks, Jesus Rubio-Melón and Wilma Vink
 The Department of Experimental High Energy Physics of the Radboud University Nijmegen for occasional hardware donations.
 The Department of Computers and Communication of the science faculties of the Radboud University Nijmegen for occasional hardware donations, backup service, and network administration.
 This work is part of the research programme of the Stichting voor Fundamenteel Onderzoek der Materie (FOM) , which is financially supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) . (1994-1995)
 This site could be maintained thanks to support of the Australian Research Council and the Flinders University of South Australia (1996-1997)

And of course all users who made invaluable suggestions and reported bugs and other inconsistencies. 23 July 2024